a) Field of the Invention
The invention relates to the inhibition of mammalian topoisomerase II and of the growth of malignant cells and to inducing the regression of malignant cells in mammals by the action of certain (S)-3-methyl-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]benzoxazine(and benzothiazine)-6-carboxylic acids; and to certain of such compounds which are novel.
b) Information Disclosure Statement
Hayakawa et al. U.S. Pat. No. 4,382,892, issued May 10, 1983, discloses antibacterial pyrido[1,2,3-de][1,4]benzoxazine derivatives having the formula ##STR2## wherein X is a halogen atom, R is a hydrogen atom or an alkyl group of 1 to 6 carbon atoms and Z represents mono-substituted, di-substituted or cyclic-substituted amino group which may contain a hetero atom and may have a substituent such as hydroxyl, alkyl having 1 to 6 carbon atoms, amino, hydroxyalkyl having 1 to 6 carbon atoms or mono- or di-alkylamino having 1 to 6 carbon atoms in each alkyl moiety.
D. T. Chu U.S. Pat. No. 4,540,694, issued Sep. 10, 1985, discloses antibacterial pyridine-substituted quinobenzoxazines having the formula ##STR3## wherein X is halogen or hydrogen; R.sub.2 is a substituent; and R.sub.1 is hydrogen or a carboxy protecting group. The specification of the patent suggests substitution on the pyridine ring including alkyl groups but there are no specific examples thereof.
Hutt et al. U.S. Pat. No. 4,571,396, issued Feb. 18, 1986, discloses antibacterial quinolones which include compounds of the formula ##STR4## wherein R.sub.1 is hydrogen, C.sub.1-6 alkyl or a cation, Y is hydrogen, fluoro or amino, W is O, NR, S or CH, R.sub.3 and R.sub.4 are hydrogen or C.sub.1-3 alkyl, and Z is an aza- or diazabicycloalkyl radical.
Gilligan et al. U.S. pat. No. 4,623,650, issued Nov. 18, 1986 discloses antibacterial quinolones of the formula ##STR5## wherein R.sub.1 is hydrogen, alkyl of 1 to 6 carbon atoms, benzyl or a pharmaceutically acceptable cation; R.sub.2 is hydrogen or fluoro; R.sub.2 and Y, inter alia, when taken together have the formula --X--(CH.sub.2).sub.n --CHR.sub.4 -- wherein X is CH.sub.2, O, S, NH or NCH.sub.3, n is 0, 1 or 2, and R.sub.4 is selected from the group consisting of hydrogen, alkyl and haloalkyl of 1 to 3 carbons, hydroxymethyl, hydroxyethyl, aminomethyl, phenyl and methylene; and R.sub.3 is phenyl which may be substituted by one to three defined substituents including C.sub.1-4 alkyl. The only specific compounds disclosed where R.sub.2 and Y are --X--(CH.sub.2).sub.n --CHR.sub.4 -- are Example 43 (R.sub.1 =H, R.sub.3 =phenyl, X=O, n=1, and R.sub.4 =CH.sub.3) and Example 44 (R.sub.1 =H, R.sub.3 =4-aminosulfonylphenyl, X=O, n=1, and R.sub.4 =CH.sub.3).
Gilligan et al. U.S. Pat. No. 4,636,506, issued Jan. 13, 1987, discloses antibacterial quinolones of the formula ##STR6## wherein R.sub.1 is hydrogen, a pharmaceutically acceptable cation or alkyl of 1 to 3 carbon atoms; R.sub.2 is 3-pyridyl or 4-pyridyl which may be substituted by various groups not including alkyl; and, inter alia, R.sub.3 and Y may be combined to form a bridge of the formula --X(CH.sub.2).sub.n --CHR.sub.4 -- or --X(CH.sub.2).sub.n --C(.dbd.CH.sub.2)-- wherein X is CH.sub.2, O, S, NH or NCH.sub.3 ; n is 0, 1 or 2, and R.sub.4 is selected from the group consisting of hydrogen, alkyl and halo alkyl of 1 to 3 carbon atoms, hydroxymethyl, hydroxyethyl, aminoethyl and phenyl. The only specific compounds disclosed where R.sub.3 and Y are combined are Example 7 (R.sub.1 =H, R.sub.2 =3-pyridyl, and combined R.sub.3 and Y=--S--CH.sub.2 --CH.sub.2 --) and Example 8 (R.sub.1 =H, R.sub.2 =3-pyridyl, and combined R.sub.3 and Y=--N(CH.sub.3)--CH.sub.2 --CH.sub.2 --).
Lesher U.S. Pat. No. 4,839,355, issued Jun. 13, 1989, discloses antibacterial fluorinated 10-(2,6-dimethyl-4-pyridinyl)-7-oxo-2,3-dihydro-7H-pyrido[1,2,3-de][1,4]be nzoxazine-6-carboxylic acids and -benzothiazine-6-carboxylic acids of the formula ##STR7## wherein R is hydrogen, R' is hydrogen or fluoro, R" is alkyl of 1-3 carbon atoms and X is O or S.
M. R. Jefson et al., at the 29th Interscience Conference on Antimicrobial Agents and Chemotherapy held Sep. 17-20, 1989, disclosed the synthesis and properties of optically pure C.sub.7 -heteroaryl quinolones structurally related to ofloxacin. Included in the properties studied was the in vitro DNA gyrase and mammalian topoisomerase activities of S-(-)-CP-92,121 [(S)-9-fluoro-3-methyl-10-(4-pyridyl)-7-oxo-7H-pyrido[1,2,3-de][1,4]benzox azine-6-carboxylic acid] and its antipode, R-(+)-CP-91,120; and S-(-)-CP-100,964 [(S)-9-fluoro-3-methyl-10-(6-quinolyl)-7-oxo-7H-pyrido[1,2,3-de][1,4]benzo xazine-6-carboxylic acid] and its antipode, R-(+)-CP-100,965. The calf thymus topoisomerase II activities, expressed as CC.sub.50 s (.mu.g/ml), for these compounds was 30, 380, 20 and &gt;1000 respectively. It is stated that the combined potent activity against procaryotic and eucaryotic topoisomerase enzymes make agents such as CP-92,121 and CP-100,964 attractive compounds for potential use as cancer chemotherapeutants.
K. Hoshino et al., Antimicrobial Agents and Chemotherapy, 33(10), 1816-1818 (October 1989) compared the in vitro inhibitory effect of certain quinolones on bacterial DNA gyrase of Escherichia coli KL-16 and topoisomerase II of fetal calf thymus. Included in the comparison are ofloxacin [9-fluoro-3-methyl-10-(4-methyl-1-piperazinyl)-7-oxo-2,3-dihydro-7H-pyrido [1,2,3-de][1,4]benzoxazine-6-carboxylic acid], fleroxacin [6,8-difluoro-1-(2-fluoroethyl)-7-(4-methyl-1-piperazinyl)-1,4-dihydro-4-o xo-3-quinolinecarboxylic acid], ciprofloxacin [1-cycloproyl-6-fluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxo-3-quinolinecarb oxylic acid], CI-934 [6,8-difluoro-1-ethyl-7-[3-(ethylaminomethyl)-1-pyrrolidinyl]-1,4-dihydro- 4-oxo-3-quinolinecarboxylic acid] and lomefloxacin [6,8-difluoro-1-ethyl-7-(3-methyl-1-piperazinyl)-1,4-dihydro-4-oxo-3-quino linecarboxylic acid], the 50% inhibitory doses for topoisomerase II of which were found to vary between 64 and 1,870 .mu.g/ml, the potency of inhibition being lowest for ofloxacin.
P. Hussy et al., Antimicrobial Agents and Chemotherapy, 29(6), 1073-1078 (June 1986) investigated the effect of certain 4-quinolones and novobiocin on elements of eucaryotic DNA replication in vitro. Ciprofloxacin, norfloxacin [1-ethyl-6-fluoro-7-(1-piperazinyl)-1,4-dihydro-4-oxo-3-quinolinecarboxyli c acid] and ofloxacin were included in the investigation and found to have K.sub.i values of 50% inhibition of DNA topoisomerases from calf thymus of 150, 300 and 1300 .mu.g/ml respectively in the case of topoisomerase II.
J. F. Barrett et al., at the 27th Interscience Conference on Antimicrobial Agents and Chemotherapy held Oct. 4 to 7, 1987, disclosed that several quinolones and anti-tumor compounds were tested as inhibitors of purified eukaryotic topoisomerase II in unknotting, catenation and radiolabeled DNA cleavage assays. Among the quinolones tested, ciprofloxacin and norfloxacin were reported not to be potent enhancers of DNA cleavage mediated by topoisomerase II whereas, in contrast, CP-67,015 [6,8-difluoro-1-ethyl-7-(4-pyridyl)-1,4-dihydro-4-oxo-3-quinolinecarboxyli c acid] induced significant DNA cleavage in both the radiolabeled and cold cleavage assays [see also J. F. Barrett et al., Antimicrobial Agents and Chemotherapy, 33(10), 1697-1703 (October 1989)].